All those choices!

Electrically assisted bikes, trikes, etc.
mattsccm
Posts: 3600
Joined: 28 Nov 2009, 9:44pm

All those choices!

Postby mattsccm » 18 Oct 2020, 10:41pm

This may be simple but so am I. My brother is sniffing round the ebike scene. Hardtail MTB really. We can't find a guide anywhere to the pros and cons of each set up. Eg wheel or BB. So many questions so askinfg each one is so long winded and tends to dissolve into thread drift. A good example if a question might be"how can hub motors work when they are the wrong side of the gears?"
A compendium of advice is sought. Pedelecs is not the answer.
Help!

stodd
Posts: 348
Joined: 6 Jun 2018, 10:24am

Re: All those choices!

Postby stodd » 19 Oct 2020, 9:09am

There are quite a few sites with comparisons; but no place a know with a single compendium of advice. Lots of reading of Pedalecs is probably as close as you will get; though I admit that you may learn more about the contributors than about the bicycle systems.

A short simple (so simple it can immediately be attacked) answer is:
* For commuting use a hub drive, for simplicity, reliability and less wear on transmission
* For mountain biking use a crank drive for power quickly available in the way you need it.

Many will agree with that, but I admit it is far from consensus opinion. And of course there are exceptions, such as a commute with big hills.

Phil Fouracre
Posts: 881
Joined: 12 Jan 2013, 12:16pm
Location: Deepest Somerset

Re: All those choices!

Postby Phil Fouracre » 19 Oct 2020, 2:14pm

Interesting post! I assume you cycle, judging by the number of posts, so why dismiss Pedelecs for info, and why ask such a strange question about hub motors?
It’s not ‘rocket science’! There’s reams of every sort of tech info available on the net. Hub motor applies power dependent on assist level or throttle, if available. Crank motor likewise, but, utilises gears as well, simples!
Never attribute to malice that which is adequately explained by stupidity

hemo
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Joined: 16 Nov 2017, 5:40pm
Location: West Sussex

Re: All those choices!

Postby hemo » 19 Oct 2020, 5:29pm

A mid motor drives thru the chain wheel so the drive in general will wear faster then a hub motor drive. For proper off road use then yes a mid motor is recommended but that doesn't mean one will suit all. I ride off road and use a 700c bike with hub drive and 40mm tyres, it takes me to the South or North Downs and is then used on any surface and any where I choose to ride. For instance on the S.D's I don't just use the SDW but any track, byway or field that I'm allowed to ride.

I have had three kit mid motor's all which have failed and none are as reliable as a hub motor kit, hence why I am a firm believer of hub motor reliability.

mattsccm
Posts: 3600
Joined: 28 Nov 2009, 9:44pm

Re: All those choices!

Postby mattsccm » 21 Oct 2020, 5:44pm

Phil, Pedelecs is way to big to get what I had hoped would be a simple answer.It is full of technical discussions by experts or specifc questions by novices. Discussions end up arguing about the pros and cons of such and such a motor. Something much more simple but comprehensive is what I am after. Ie the pros and cons of each system and why.
My brother has tried everything form 6k full suspension MTBs with BB motors to cheap conversions with rear hub motors. He liked bits of all of them but disliked bits. As a novice he wants some facts.

stodd
Posts: 348
Joined: 6 Jun 2018, 10:24am

Re: All those choices!

Postby stodd » 21 Oct 2020, 8:40pm

I'm afraid you can either have simple or comprehensive but not both. Comprehensive is bound to cover detailed discussions on different motors, for example. He isn't really a novice any more if he has had the chance to try all those different machines.

MarcusT
Posts: 339
Joined: 31 Jan 2017, 10:33am

Re: All those choices!

Postby MarcusT » 23 Oct 2020, 5:35am

Youtube
Search 'choose an ebike' and....voila
I wish it were as easy as riding a bike

Boyonabike
Posts: 14
Joined: 22 Oct 2019, 10:46pm

Re: All those choices!

Postby Boyonabike » 25 Oct 2020, 8:32am

Main decisions are type of motor and type of sensor.

Sensors can either be cadence (checks pedals are turning and if so applies power to motot) or torque ( measures force on pedals and applies power in proportion to your pedalling force).

Motor can be either wheel or bottom bracket.

Cadence pros: cheap, bike will get you home if chain snaps as long as your feet are turning the pedals.
Cadence cons: doesn't feel natural as bike will move at a fixed speed if you turn pedals, drains battery faster.
Torque pros: more natural feeling as though hills are flat and there is a gentle tailwind pushing you along
Torque cons: more expensive.

Front hub motor pros: easiest to convert an existing bike, works with hub gears, less chain wear than bottom bracket motor, cheaper
Cons: slippage on gravel so unsuitable for MTB, feels like bike is pulling you (slightly odd to describe but some might actually like it as you effectively have a two wheel drive bike), can't use front hub dynamo lights

Rear hub motor pros: less chain wear, least visible motor if you want your bike to not look like an ebike and have a small battery, less chain wear than bottom bracket motor, compatible with derailleur gears, cheaper
Cons: wheelies if pedal too aggressively

Bottom bracket pros: more power, better battery life, more natural feeling, compatible with hub gears and derailleur and can use front hub dynamo
Cons: more expensive, may be harder to retrofit, more chain wear than hub motor

Most but not all hub motor ebikes are paired with a cadence sensor and most but not all mid motors pair with a cadence sensor.

Think about lighting as not all ebikes will use the motor battery to power the lights.

I have a torque sensor front hub motor rear hub gear evoke and my wife has a Torque sensor rear hub motor ebike . Both perfect in different ways for commuting.
Last edited by Boyonabike on 26 Oct 2020, 10:17pm, edited 2 times in total.

stodd
Posts: 348
Joined: 6 Jun 2018, 10:24am

Re: All those choices!

Postby stodd » 25 Oct 2020, 9:23am

Good summary by Boyonabike.
One extra advantage of cadence sensors is that you still get power if you 'ghost' pedal, keep the pedals turning but don't apply any pressure. That can be really helpful if you are tired and hit a big hill near home, and also good for people with certain disabilities

hemo
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Joined: 16 Nov 2017, 5:40pm
Location: West Sussex

Re: All those choices!

Postby hemo » 25 Oct 2020, 9:46am

Generally agree with most of them.
Rear hub bike wheelie not very likely unless you go illegal with high power hub with higher current and voltage.
Mid drive bike with CAN bus closed system, expensive to repair once any two year warranty has run out.

Oldjohnw
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Joined: 16 Oct 2018, 4:23am
Location: Northumberland

Re: All those choices!

Postby Oldjohnw » 25 Oct 2020, 9:46am

I have a front hub torque sensor. I do indeed get a bit of wheelspin when on gravel, fully loaded at rear and a very steep hill. I fell off once.
John

Phil Fouracre
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Joined: 12 Jan 2013, 12:16pm
Location: Deepest Somerset

Re: All those choices!

Postby Phil Fouracre » 25 Oct 2020, 11:08am

Some great comments! Like everything you have to make a decision finally - you can read all the opinions in the world, but....
We’ve had front hub, rear battery - rear hub, rear battery (you’ll never go over the bars on this!) and now got crank motor, integrated frame battery and full suss - magic!! Best of luck.
Never attribute to malice that which is adequately explained by stupidity

mumbojumbo
Posts: 773
Joined: 1 Aug 2018, 8:18pm

Re: All those choices!

Postby mumbojumbo » 26 Oct 2020, 6:26am

Suggest you read this article which illustrated dagers of seeking the best of anything,

https://www.swarthmore.edu/SocSci/bschwar1/Sci.Amer.pdf

Buy something to ride and if you dont like sell and replace ie discover for yourself.Focus on your ride and not the technology.The best meals are often made on the most basic cookers.Our old lass used to cook two joints,3 puddings and 5 veg on a 3 ring stove powered by wedges of peat.

mattsccm
Posts: 3600
Joined: 28 Nov 2009, 9:44pm

Re: All those choices!

Postby mattsccm » 30 Oct 2020, 10:27pm

Cheers. I will stay here as i am getting somewhere. But why the sensors? I understand the words cadence and torque but what do they?
We/I am after factual info about the tech. Picking a tool should be about how it works not the end result.

mattsccm
Posts: 3600
Joined: 28 Nov 2009, 9:44pm

Re: All those choices!

Postby mattsccm » 30 Oct 2020, 10:31pm

Brother wants a MTB for some fairly serious off road use. Stuff transmission wear, it will be cheaper than his motorcycles.
What he wants is something that gives him Chris Hoys legs without thinkjng about it. What he hasn't realised is that it will be crap on tbe gravel as he'll have to pedal a heavy old lump at 16mph :D